1. Field of the Invention
The present invention relates to azido-substituted octopamine agonists, and the radio-labeled derivatives thereof, having pest controlling activity and to methods of controlling pests by treatment with the aforementioned octopamine agonists. The invention also relates to an apparatus comprising a support structure, the azido-substituted octopamine agonists of the invention, and a UV light source. The invention also relates to methods for the isolation of octopamine receptor proteins utilizing the radiolabeled azido-substituted octopamine agonists of the invention.
2. Description of the Background Art
Despite the recent development and great promise of such advanced pest controlling compositions as chemical sterilants, pheromones or ecologically-based insect control strategies, it is doubtless that, at present, the use of chemical pesticides still plays a predominant role. The use of insecticides often represents the difference between profitable crop production for farmers and no marketable crop at all. The value of insecticides in controlling human and animal diseases has been dramatic.
Therefore, in parallel to the aforementioned newer technologies for pest control, there has been active research and investigation into the detailed biochemical modes of action of chemical pesticides. Thus, for example, Nathanson et al., Molecular Pharmacology 20:68-75 (1981) presented evidence indicating that the formamidine pesticides chlordimeform (CDM) and N-demethylchlordimeform (DCDM) may affect octopaminergic neurotransmission. CDM and DCDM have been reported to mimic the effects of octopamine in stimulating light emission in the firefly lantern (Hollingworth, R. M. et al., Science 208:74-76 (1980)), and in effecting nerve-evoked muscle responses in the locust leg (Evans, P. D., Nature 287:60-62 (1980)). Nathanson et al., supra, found that DCDM, the probable in vivo metabolite of CDM, is about six-fold more potent than octopamine itself as a partial agonist of adenylate cyclase stimulation. Stimulation by the formamidines results in increased formation of the intracellular messenger, cyclic AMP. This stimulation was blocked by cyproheptadine, clozapine, fluphenazine and phentolamine compounds, also known to block the octopamine receptor. Nathanson et al. concluded that DCDM is the most potent octopaminergic compound described.
Similar results were observed by Hollingworth et al. (reported in the Scientific Papers of the Institute of Organic and Physical Chemistry of Wroclaw Technical University, No. 22, Conference 7 (1980)). These authors demonstrated that certain formamidines act on octopamine receptors to induce the synthesis of cyclic AMP, and that this response is blocked by both phentolamine and cyproheptadine, which are known to act as octopaminergic antagonists in insects. The authors also suggested that these formamidines are potent simulators of the octopamine sensitive adenylate cyclases in the thoracic ganglia of Periplaneta americana, and in the ventral nerve cord and fat body of M. sexta. The authors suggest that the stimulation of octopamine receptors underlies a number of toxic responses seen with formamidines on insects.
However, use of formamidines as pest controlling agents gives rise to certain problems, including the fact that the aniline breakdown products are carcinogenic. Moreover, a further problem is that the range of activity of these compounds is limited to a relatively few insect species. Matsumura, F., et al.. Environ. Health Perspect. 14: 71-82 (1976). Applicant has observed that didemethylchlordimeform (DDCDM) is a full agonist, 20-fold more potent than octopamine in Manduca. but only a very weak and partial agonist in the cockroach. Consistent with this in vitro activity, the formamidines are toxic in Manduca but not in the cockroach.
It should be noted that the presence of an insect adenylate cyclase enzyme which is sensitive to naturally occurring D(-) octopamine as a "neurotransmitter" has been known for some time (Nathanson et al., Science 180:308-310 (1973) (cockroach); Nathanson, ibid. 203:65-68 (1979) (firefly); Evans, J., Neurochem. 30:1015-1022 (1978) (cockroach)).
The study of cyclic AMP (cAMP) as a "second messenger" has led to the accepted model that a hormone or neurotransmitter binds at a cell-membrane bound receptor, which activates adenylate cyclase to a form capable of converting ATP in the cytoplasm of the cell into cAMP. cAMP then relays the signal brought by the hormone or neurotransmitter from the membrane to the interior of the cell. Agonists of the hormone or neurotransmitter are, by definition, capable of eliciting the same response (see, for example, Nathanson and Greengard, Scientific American 237:108-119 (1977)). Once formed inside the cell, cAMP presumably binds to a protein kinase which is then capable of phosphorylating appropriate proteins, etc.
Recently, a class of octopamine receptor agonists comprising substituted phenyliminoimidazolidines have been described. These compounds show antifeeding activity in Manduca sexta and interact with octopamine receptors which are distinct from mammalian adrenergic (including alpha-1, alpha-2, beta-1, beta-2), dopaminergic, 5HT.sub.1, and 5HT.sub.2 receptors. Nathanson, J. A. in "Abstr. 2nd Internatl. Sym. Insect Neurobiol. Pest Action," Society of Chemical Industry, London (1985); Nathanson, J. A., Proc. Natl. Acad. Sci. (USA) 82:599-603 (1985); and Nathanson, J. A., Mol. Pharmacol. 28:254-268 (1985).
In order to allow development of further octopamine agonists which are effective against a wide variety of insect species and which
In order to allow development of further octopamine agonists which are effective against a wide variety of insect species and which have a wide spectrum of pesticidal activity, a need exists for additional information about the molecular pharmacology of octopamine receptors and the interspecies differences in the characteristics of these receptors.